import { LitElement } from 'lit';
/**
 * Video background with a blurred thumbnail placeholder that crossfades into
 * the full-resolution image once it has finished loading.
 *
 * Slot this into `sw-ui-call-layout`'s `background` slot.
 *
 * @prop {boolean} [default]    - Use the built-in SignalWire background image
 * @prop {string}  thumbnail    - Data URL shown immediately as a blurred preview
 * @prop {string}  src          - URL of the full-resolution background image
 * @prop {string}  [blurAmount] - CSS blur amount applied to the thumbnail (default: 20px)
 *
 * @csspart thumb - Blurred low-res thumbnail layer.
 * @csspart image - Full-resolution image layer (fades in once loaded).
 */
export declare class SwUiBackground extends LitElement {
    static styles: import("lit").CSSResult;
    default: boolean;
    thumbnail?: string;
    src?: string;
    blurAmount: string;
    private _loaded;
    private get _src();
    private get _thumbnail();
    willUpdate(changed: Map<string, unknown>): void;
    render(): import("lit-html").TemplateResult<1>;
}
declare global {
    interface HTMLElementTagNameMap {
        'sw-ui-background': SwUiBackground;
    }
}
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